Preparation of polydioxolane



Patented Dec. 28, 1948 SEARP,

PREPARATION OF POLYDIOXOLANE William F. Gresham, Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application July 3, 1945, Serial No. 603,111

9 Claims.

This invention relates to a process for the preparation of polymers of 1,3-dioxolane and to the polymeric products.

This application is a continuation-in-part of S. N. 392,124, filed May 6, 1941, issued February 12, 1946, as U. S. 2,394,910.

Heretofore, it was known that cyclic acetals having more than 5 and preferably more than 6 members were polymerizable, while those skilled in chemistry knowing the stability of the 5-member ring, were of the belief that it would not polymerize. The literature on the preparation of linear polymers has avoided by and large the five-member ring compounds apparently because the experimenters in the art, knowing the stability of this ring, were convinced they could not be polymerized. Attention accordingly was directed to the less stable compounds known to be polymerizable such as those having 6 or more atoms in the ring.

An object of the present invention is to provide new polymeric forms of matter and processes for their preparation. Another object is to provide new polymeric compositions from 1,3-dioxolane. Still another object is to provide a process for the polymerization of 1,3-dioxolane, its isomers and metamers. Another object of the invention is to provide mixtures or interpolymers of 1,3-dioxolane with its isomers, its metamers, substituted 1,3-dioxolanes and with the cyclic and allcycllc alkylene oxides. Yet another object is to provide polymers containing the repeating ethenoxymethenoxy group, [CH2CI-IzOCH-2Ol1 in which a: is more than 1. Other objects and advantages of the invention will hereinafter appear.

It has been found that 1,3-dioxolane can be polymerized to give polymers having a range of properties from liquids to solids by contacting it with a suitable catalyst under properly controlled conditions. The reaction possibly proceeds in accord with the equation:

OCH2 X Cz --r (-CHzOCH2CH20-)= O- Hz The polymeric product designates a repeating ethenoxymethenoxy group in which a: is greater than one although unsymmetrical and cross linkages may exist in the polymer produced. When a: is less than ten. the product is usually a mobile to viscous liquid, with a: greater than ten the products are generally solids, while with molecular weights in the order of 10,000 or more the polymers are tough, cold-drawable solids.

The polymerization is effected at temperatures ranging between C. and 300 C. and preferably between 0 and 150 C. Atmospheric, subor superatmospheric pressures may be used and if the last, pressures may range between 1 and atmospheres or higher. Normally, excellent results are obtained at or above atmospheric pressure. If desired, the temperature of the reaction, especially when polymerization is carried out at the boiling point of the cyclic compound, may be controlled by varying the pressure on the boiling reactants.

It has been found advantageous to effect the polymerization in the presence of a catalyst such, for example, as sulfuric acid, phosphoric acid, hydrochloric acid, hydrofluoric acid (alone or with BFa), boron fluoride (including its complexes with water, acids, esters, alcohols, and the like), paratoluene sulfonic acid, camphor sulfonic acid and other acid catalysts of this general nature. Friedel-Crafts type catalysts other than BF: may be used such as AlCh, AlBrx, F'eCla, etc., as may be inorganic acids generally, and their acid salts such as sodium acid sulfate, sodium acid phosphate, etc.

The catalyst may be supported or not or inert supports such as charcoal, silica gel (which is alone a catalyst for the reaction), kieselguhr, etc. Concentrations of BFs, E2804, and similarly strong acid catalysts may be extremely low, less than 0.1% and amounts down to as low as 0.001% of these strong acid catalysts have been found suflicient to give polymers a though high concentrations of catalyst even equal to the weight of the 1,3-dioxolane were likewise found to be satisfactory.

The polymerization of 1,3-dioxolane may be carried out by a one-step or a multiple-step process. In the former the 1,3-dioxolane, together with a suitable polymerization catalyst, may be heated under a reflux condenser or may be allowed to stand at room temperature or below, until the desired molecular weight polymer forms. Polymerization occurs as has been indicated, over a wide range of temperatures and doubtless the polymerization starts as soon as a polymerization catalyst is added to the monomeric compound. If temperatures are employed above the boiling point of the cyclic acetal, a reflux condenser is employed, or, if desired, pressure may be substituted in order to prevent the loss of the monomer which otherwise would distill off during the early stages of the reaction.

In contradistinction to the one-step process, the process may be carried out in a plurality of 56 stages. For example, in the first stage the 1,3-

dioxolane can be heated, under refiux until boiling ce'ses, the catalyst neutralized and separated and the product, which under these conditions is polymerized to low molecular weight or mixtures of low molecular weight products (or may be a monomer-polymer mixture), can be used in this form or at a subsequent time it can be subjected to further polymerization under similar or difierent polymerization conditions. This versatility of polymerization control can also be attained by carrying out the first stage under low temperature conditions and completing the polymerization at high temperatures or vice versa.

By the two-step process, it is possible to effect the final polymerization in a locus in which polymerization by the single-step polymerization process would be difiicult if not impossible. For example, fabric may be impregnated with the incompletely polymerized mixture with or without catalyst and the fabric ironed to attain the final stages of polymerization in situ, or such a mixture may be inserted, after addition of the catalyst, in a mold or injected into a biological specimen or other enclosed space and polymerization completed therein.

The polymerization may be conducted in such a manner that the final products range in properties from liquids to solids. A short time and high rate of polymerization usually result in the more fluid liquids, while the more extended time and slow rate of polymerization usually result in the formation of highly viscous to wax-like solids and, under properly controlled conditions, tough cold-drawable solids.

Tough films can be prepared by dissolving the high molecular weight polymers in water to give a solution containing in the order of polymer, flowing the solution on a suitable surface, and allowing the water to evaporate at atmospheric or reduced pressures. The film when stripped from the surface can be stretched to give the superior strength to the film resulting from cold drawing. Lower molecular weight polymers will give films of lower strength. Films can likewise be obtained by preparing a powder from the polymer by filing, grinding, or otherwise treating it and by thermoplastic molding forming the sheet which can be stretched as described.

The reaction mixture, after partial (by the first step of the two-step process) or complete polymerization, may be treated with an inorganic base (such as ammonia, alkali metal, and alkaline earth metal hydroxides, carbonates, alkoxides, etc.) or an organic base (such as pyridine, methyl amine, and dimethyl amine) to neutralize the catalyst (immediately upon neutralization it is believed that the polymerization reaction ceases) and the unconverted reactants may be removed by distillation under reduced pressure. The neutralized catalyst may be filtered ofi, remaining polymerized product recovered, purified if desired by solution in a suitable solvent, and clarified with kieselguhr or other similar material. In addition to being instrumental in stopping the reaction at the desired point the neutralization of the catalyst stabilizes the product. It follows, therefore, that for high temperature uses no acids should be present and the product should be neutral or on the alkaline side.

1,3-dioxolane may be polymerized in various ways. The polymerization may be carried out by treating the monomer and catalyst in the presence or absence of a solvent for the monomer and polymer and for this type of polymerization such solvents as 1,4-dioxane, benzene, toluene, etc.

may be used. If desired, polymerization can be effected in a solvent for the monomer which is a non-solvent for the polymer; by this method the polymer will precipitate from solution as formed. For polymerization in this manner, 1,3-dioxolane can be polymerized in cyclohexane which is a solvent for the monomeric but not for the polymeric 1,3-dioxolane.

1,3-dioxolane products, having a wide range of physical and chemical properties, can be made by its simultaneous polymerization in contact with substituted 1,3-dioxolane and the epoxides. Compounds of this nature are in many instances interpolymers although not necessarily so. For the preparation of such compounds, 1,3-dioxolane can be polymerized with the epoxides such as ethylene oxide, 1,2 and 1,3-propylene oxides, tetrarnethylene oxide, isobutylene oxide and their isomers and metamers. 1,3-dioxolane can likewise be polymerized while in contact with substituted 1,3-dioxolanes such as 4-methyl-l,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 4,4-dimethyl-L3-dioxolane, 4-ethyl-L3-dioxolane, 4-phenyl-1,3-dioxolane; the cyclic acetals, such, for example, as 2-alkyl substituted 1,3-cyclic acetals, e. g. 2- methyl-1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2-nand 2-isopropyl-1,3-dioxolane, 2-nand 2-isobutyl-1,3-dioxolane and higher z-alkyl substituted cyclic acetals as well as the cyclic ketals 2,2- dimethyl-1,3-dioxolane, 2,2-diethyl-1,3-dioxolane, 2-methyl-2-ethyl-1,3-dioxolane, etc. The aryl substituted 1,3-dioxolanes such, for example, as 2-naphthyl-1,3-dioxolane, 2-phenyl-1,3-dioxolane; the aralkyl substituted 1,3-dioxolanes such as Z-p-methylphenyl-1,3-dioxolane; 2-hydroxy methyl-1,3-dioxolane U-GHz obtained from glyoxal and ethylene glycol may likewise be treated in accord with the invention. Products having a wide range of properties can be obtained by varying the ratio of the monomers.

The partially polymerized or fully polymerized cyclic acetals of the invention may also be mixed with the monomeric or partially or fully polymerized substituted or unsubstituted 1,3-dioxolanes, substituted or unsubstituted 1,3-dithiolanes, or the epoxides mentioned above. By this means interpolymers and mixed polymers having a wide range of characteristics are obtained.

1,3-dioxolane polymers, interpolymers, mixed polymers, and monomer-polymer mixtures may be further modified before or after polymerization by substances which will dissolve in the monomer and/or polymer and thereby render the resulting composition more flexible and resistant to moisture, oil, and the like. There may be selected from the classes normally recognized as plasticizers or from those actually classed as plastics, film formers, etc. While in many instances plasticizing and softening agents are not completely miscible or soluble in the polymers of the invention, nevertheless generally they are sufficiently soluble to give many desirable plasticizing and softening efiects.

Polymeric 1,3-dioxolane, either plasticized or OEHRLJ not, may be formed as slabs, discs, or sheets, and as such may be used in the manufacture of unsplinterable glass. It is also within the scope of the invention to add filling materials (e. g. china clay, wood flour, asbestos, etc.) and/or colouring matters, soluble and insoluble, to the polymerization product prior to polymerization. Such materials as metallic powders, crushed mica, may be added in a similar way.

Examples will now be given illustrating embodiments of the invention, but it will be understood that it will not be limited by the details thereof. Parts are by weight unless otherwise indicated.

Polymerization of 1,3-dz'0xolane Example 1.A mixture containing 417 parts of 1,3-dixolane and 2 parts of sulfuric acid was heated on a Water bath under a return condenser for 5 hours. At the end of the first hour the mixture became viscous and boiling ceased. The catalyst was made alkaline to phenolphthalein by treatment of the warm products with anhydrous ammonia followed by 2.1 parts of sodium hydroxide and parts of water. The unconverted 1,3- dioxolane amounted to 60 parts and was removed under reduced pressure. The residue was dissolved in benzene, filtered to remove precipitated matter and the benzene diluent removed under reduced pressure. There remained 350 parts of a wax-like, colorless solid miscible with water, benzene, and methanol. It had a meltin point between 52 and 58 C. and an apparent molecular weight of 826, estimated by the boiling point method (0.5 to 1.0% of the polymer in benzene).

Example 2.-A reaction mixture containing 895 parts of carefully purified 1,3-dioxolane and 2 parts of sulfuric acid was heated on a water bath under a return condenser carrying a drying tube, for 8.5 hours. The roduct was cooled and unconverted dioxolane, 164 parts, removed by distillation at 2 mm. pressure. During this operation the polymer solidified. It was melted and heated on the water bath for 1.75 hours. The distillation was repeated whereupon 68.9 parts of dioxolane was removed. The remaining polymer plus catalyst was heated 7 hours on the water bath. Subsequent to neutralization of the catalyst with anhydrous ammonia until alkaline to phenolphthalein followed by 1.8 parts of sodium hydroxide in 10 parts of water. 594 parts of colorless, wax-like solid polydioxolane was obtained after removal of 68.9 parts of dioxolane under reduced pressure. This solid polymer, molecular weight of 2400 as estimated by the procedure described in Example 1, was only slightly soluble in benzene at ordinary temperature, soluble in hot benzene and soluble in water.

Example 3.-A reaction vessel was charged with 88.8 parts of 1,3-dioxolane and 0.25 part of concentrated sulfuric acid. The charge was heated to a temperature between 89 and 92 C. for 5 hours on total reflux, the reaction being carried out at atmospheric pressure with continuous stirring. The vessel was heated during the reaction by steam coils and the pot temperature prevented from exceeding 100 C. After cooling to between 60 and 70 C., anhydrous ammonia was introduced into the reaction mixture until alkaline to phenolphthalein. Sodium hydroxide equivalent to the sulfuric acid catalyst was then added as a 50% solution in water. Ammonia and unreacted dioxolane were removed at atmospheric pressure by distillation and the distillation continued under gradually reduced pressure to 6 mm. A yield of 61 parts of polydioxolane was obtained.

Example 4.A reaction vessel was charged with 88.2 parts of 1,3-dioxolane and 0.25 part of concentrated sulfuric acid. The reaction disclosed under Example 3 was repeated and 59 parts of polydioxolane was obtained. This product had a molecular weight of approximately 1200 and a melting point of 57 .7 C.

Example 5.A mixture consisting of 231.3 parts of 1,3-dioxolane and 1 part of anhydrous BF3 was heated on the steam bath intermittently over a period of 4.25 hours. The effect of the BFa was destroyed by treatment of the product with anhydrous ammonia. Unconverted dioxolane was removed under reduced pressure while heating the product in a water bath. 190 parts of a colorless, hard, wax-like solid polydioxolane, estimated molecular weight 1580, was obtained which had a zero hydroxyl number as measured by the procedure of Smith 8: Bryan, J. A. C. S. vol. 57, page 61 (1935). It is believed that the product obtained contains cyclic polymers such as (OCHzCHzOCHi) CH2OCH2CH2O z in which x is an integer.

Example 6.To 155.5 parts of 1,3-dioxolane was added 1 part of sulfuric acid. After standing at room temperature for 3 days, a colorless solid polymer was formed.

Example 7.To 132.1 parts of 1,3-dioxolane was added 5 g. of 14 mesh silica gel catalyst. The mixture was boiled 14 hours under a return condenser. Removal of the catalyst and unconverted dioxolane gave 25 parts of colorless, viscous liquid polydioxolane which was miscible with water and benzene.

Example 8.Five parts of Filtrol x-l43 (an activated clay) was added to 158.7 parts of 1,3- dioxolane and the mixture heated on a water bath for 5.75 hours. Removal of the catalyst by filtration and unconverted dioxolane, 35.3 parts, by heating on a water bath under reduced pressure gave 120 parts of a colorless solid polydioxolane.

Example 9.-To 225 parts of carefully purified 1,3-dioxolane was added about 0.05 part of anhydrous BF; catalyst and the reaction mixture was set aside at room temperature. At the end of 3 days the 1,3-dioxolane had polymerized to a colorless tough polydioxolane of high molecular weight. A film prepared from this polydioxolane exhibited the following properties:

2680 #/sq. in.

Tensile strength Elongation at break Pfund flex (as measured by the Pfund flexing machine)--- Above 300 with no signs of failure Cold draw Excellent (cold drawn material has a 20 25% elastic stretch) tough, horny, translucent solid material. At the end ofit'hirteen days the container broke, apparently due to the contraction of the polymeric ma terial.

The polymer was cut into thin shavings, then dissolved in hot water maintained at a temperature in the proximity of 50 C., and dilute ammonia added to neutralize the catalyst. A small amount of sodium hydroxide was subsequently added (approximately 0.1%) and the solution heated at approximately 100 C. at which temperature the polymer precipitated from the solution and after separation and washing was dried in a vacuum oven at 50 C.

The oven-dried product was a tough, flexible sheet of material which was placed between the platens of a press under a pressure of approximately 100 lbs. per sq, in. and at a temperature of 100 C. The sheet (0.015" thick) taken from the press was cut into /2" strips and tested in a tensile testing machine. The film exhibited the following properties:

Tensile strength lbs. per sq. in. 3900 Elongation at break per cent 800 Elastic recovery per cent 450 Another strip of film was stretched at room temperature to about 650% and a permanent set resulted. This cold-drawn film was then tested in a tensile testing machine and recorded a strength of 19,200 lbs. per sq. in.

Example 11.--A reaction mixture containing 400 parts of 1,3-dioxolane and about 0.2 part of boron trifiuoride was allowed to stand at room temperature for 5 days. At the end of this time, the polymer, which was a hard, tough, resin-like solid, was converted to thin shavings which were dissolved in 0.1% aqueous NH40H at 50-60 C. and precipitated from this solution at 100 C. after adding 3-4 parts of NaOH for every 50 parts of polymer dissolved. The catalyst free polymer was dried at 50 C. in a high vacuum. The properties of this treated polymer, formed into a film as described in Example were:

Appearance Tough, elastic, white Tensile strength 3020 lbs/sq. in. Elongation at break 425% Elongation recovery--- 325% Film appearance Colorless, cloudy, fiex- F ible. Cold draws well and stretches in the cold drawn state. Molecular weight 86000 (determined by viscosity of a chloroform solution) Melting point 63-70" C.

Example 12.-A reaction mixture containing 400 parts of 1,3-dioxolane and about 0.2 part of boron trifiuoride was allowed to stand for 13 days at 6 C. In three days the mixture became viscous and in 7 days had solidified. Thin shavings of the resultant solid polymer were dissolved in approximately 0.1% aqueous NH4OH at 50-60 C. and precipitated from this solution at 100 C. after adding 3-4 parts of sodium hydroxide for every 50 g. of polymer dissolved. The catalyst free polymer was dried at 50 in a high vacuum. The properties of this treated polymer formed into a film as described in Example 10 were:

Appearance Tough, elastic, white Tensile strength 4520 lbs/sq. in. Elongation at break 600% Elongation recovery to 250% Film appearance Colorless, translucent, non-tacky, flexible, tough, cold draws well and has considerable stretch in cold drawn state Molecular weight (determined by viscosity method in choloroform) 196,000

Cold drawn film Tensile strength lbs./sq. in.-- 5530 Elongation at break per cent 200 Elongation recovery to do 50 Example 13.--A reaction mixture consisting of 100 parts of anhydrous cyclohexane, 400 parts of 1,3-dioxolane and about 0.2 part of boron trifiuoride was allowed to stand at room temperature for 11 days, the cyclohexane was evaporated, and a solid polymer obtained. Thin shavings of the polymer were dissolved in about 0.1% aqueous ammonium hydroxide and precipitated from this solution at 100 C. after addin 3-4 parts of sodium hydroxide for every 50 parts of polymer dissolved. This treated polymer was dried at 50 in high vacuum. The properties of the polymer formed into a film as described in Example 10, were:

Appearance Tough, elastic, white Tensile strength 2440 lbs/sq. in.

Elongation at break 40% Elongation recovery to 5% Film appearance Colorless, cloudy. cold draws well and stretches in the cold drawn state Example 14.A reaction mixture comprising 1000 parts of 1,3-dioxolane and 1 part of sulfuric acid was boiled 15 minutes. 47 parts of a colorless viscous polydioxolane, isolated as described in Example 1, was obtained. Its molecular weight was 477.

Example 15.-A reaction mixture consisting of 156.3 parts of 1,3-dioxolane and 2.5 parts of ptoluene sulfonic acid was set aside at room temperature. At the end of six days the dioxolane had polymerized to a colorless, viscous liquid.

Example 16. Ethylene Oxide-91,3 Diozcolane Polymerizati0n.-A reaction mixture was prepared containing parts of 1,3-dioxolane, 95 parts of liquid ethylene oxide, and 1 part of anhydrous BFa, cooled in a Dry Ice-methanol bath. The mixture, so prepared, was warmed gently under a Dry-Ice cooled condenser and finally heated for 4 hours on a steam bath. A viscous colorless liquid product was obtained. Subsequent to neutralization of the catalyst with excess anhydrous ammonia, unconverted reactants were removed under reduced pressure at 1 mm. and C. The interpolymer, 122 parts, was a light brown, viscous liquid soluble in water, methanol and benzene.

Example 17.Interpolymerization of Propylene Oxide and 1,3-Dioxolane.A reaction mixture consisting of parts of propylene oxide, 100 parts of 1,3-dioxolane and ca. 1 part of BF: catalyst was heated under a return condenser for 23.5 hours. The catalyst was destroyed by treatment with anhydrous ammonia. Removal of unconverted reactants under reduced pressure gave 59 parts of a viscous light yellow liquid polymer which was soluble in methanol and benzene but practically insoluble in water,

Example 18.1,3 Diorcolane+2 phenyl 1,3- Diorolan Plymerization.A reaction mixture, prepared by addition of 3 parts of anhydrous BF: to 60 parts of 1,3-dioxolane and 60 parts of 2- phenyl-l,3-dioxolane, was heated on a steam bath for 2.75 hours. To the cooled product was added 5.3 parts of sodium hydroxide in 15 parts of water. At 2 mm. and a bath temperature of 150 0, water, 8 parts of unconverted 1,3-dioxolane, and 1 part of unconverted 2-phenyl-1,3-dioxolane were removed. Salts were removed by filtration. 94 parts of an amber-colored somewhat viscous liquid polymer, estimated molecular weight 346, was obtained which was insoluble in water and soluble in benzene and methanol.

Example 19. 1,3 Dioscolane Cyclohexanone Ethylene Glycol Cyclic Ketal Polymerization.-

A mixture comprising l1 parts of cyclohexanone ethylene glycol cyclic ketal, 740 parts of 1,3- dioxolane and 4 parts of sulfuric acid was heated on the water bath for 5 hours. Boiling ceased after heatin 1 hour with the production of a viscous liquid. The cooled reaction mixture was treated with anhydrous ammonia followed by 3.4 parts of sodium hydroxide dissolved in 12 parts of water to destroy the catalyst. Under reduced pressure 217 parts of unconverted 1,3-dioxolane and 32 parts of unconverted cyclohexanone ethylene glycolic cyclic ketal were removed. A benzene solution was filtered to remove salts. Removal of benzene under reduced pressure to 1 mm. and a bath temperature of 100 C. gave 561 parts of a light red, viscous liquid polymer, molecular weight 1130, which was miscible with water.

Solution polymerization Example 20.Polymerz'zation of 1,3-Dioxolane in 1,4-Dioa:ane Solvent.A reaction mixture prepared by mixing 100 parts of 1,3-dioxolane, 400 parts of dried, lA-dioxane and 2 parts of H2804 was heated '7 hours on a steam bath. At all times the reaction mixture was homogeneous. The catalyst was destroyed with 2 parts of sodium hydroxide dissolved in 5 parts of water. Removal of solvent and unpolymerized dioxolane gave 5 parts of a viscous liquid polymer which had a molecular weight of 248.

Polymerization in Solvent for Monomer-Won- Solvent for Polymer Example 21.-Polymerization of 1,3-Diomolane in Cyclohexane Solvent-A homogeneous reaction mixture prepared by dissolution of 100 parts of 1,3-di0xolane in 400 parts of cyclohexane containing 2 parts of sulfuric acid was heated on a water bath under a reflux condenser for '7 hours. At the end of the first hour, liquid polydioxolane began separating. On working up the product as described in Example 16, 26 parts of a viscous liquid polydioxolane was obtained.

The higher molecular weight polymers obtained in accord with the process of the invention have the unusual property of being cold drawable, and moreover, products which are cold drawn have an increased tensile strength and resistance to wear. The cold drawing may be effected by various means, for example, the molten polymer may be spread on a flat surface, such as glass, and after cooling the resulting film may be subjected to tension under which the film will stretch from 200 to 600%, to a permanent set. Other known methods of cold drawing may be employed. The cold drawing operation in addition to increasing the tensile strength of the film likewise orients the fibers and renders the film suitable for such applications in which filaments having oriented molecules are adaptable, for example, in preparation of Poloroid films and the like.

For the actual manufacture of fibers from the higher molecular weight polymers of the invention these may be spun directly from the molten polymer, or a solution made by dissolving the polymer in a solvent and the resulting mixture spun through a fine nozzle or spinneret. Thus a solution of the high molecular weight polymer is prepared either alone or together with another fiber forming material, such as the cellulose derivatives, e. g. cellulose nitrate, cellulose acetate, cellulose acetopropionate, and the like, in a mutual solvent, such as acetone or chloroform. The solution may be extruded through a fine spinneret into a chamber maintained at an elevated temperature to accelerate the evaporation of the solvent and the formation of the filament. Such a solution may, if desired, be spun into a chamber containing a liquid instead of air, the former being capable of dissolving the solvent from the polymer.

In a similar manner the polymers of the invention can be spun directly from the molten state, the spinneret being maintained at suitably elevated temperature and in this instance no sol- ,vent removal is required for the filament is formed directly upon cooling. In order to obtain the high tensile strength and wear resistance, the spun filaments or fibers should be submitted to the action of mechanical stress or stretching to produce the high orientation which gives greater strength, pliability and elasticity.

In the specification and claims attached, it will be understood that polymers and interpolymers of l,3-dioxolane and/or its derivatives refer to the product resulting from the polymerization of the monomeric compound. The exact molecular structure of the polymer resulting from the polymerization of 1,3-di0xolane is not known; in this application and the appended claims, however, the term polymeric 1,3-dioxolane will be used to indicate the polymer although it is understood that the polymer may or may not contain the cyclic form of 1,3-dioxolane.

The compounds prepared in accord with the invention may be employed for a large number of uses. The polymers which are soluble in water are suitable as additions to various baths for the treatment of natural and synthetic textiles. For example, they may be employed in washing, dyeing, after-treating, mercerizing, carbonizing, fulling, wetting, dispersing, emulsifying, and levelling operations, and furthermore, for improving the fastness of dyeings to rubbing. These polymers may likewise be used as solvents and as assistants for converting dyestuffs into pastes and as emulsifying agents, for instance, for dispersing oils, fats, and hydrocarbons.

The products dissolved or dispersed in water likewise have desirable properties so that they may be employed in such form in the textile, leather, paper, wax, and polish industries as, for example, in coating, mercerizing, dressing, bucking, finishing, printing or polishing, in the formation of carbon paper and belt dressings. In such uses the solid polymers may also be employed as wax substitutes for carnauba, Montan wax, and the like. They are likewise suitable for use in dyeing and printing because of their spreading, levelling, binding action; for example, with vat dyestufis, or with azo dyestuffs from fl-naphthoicacid arylides on the fibre, the dyeings are rendered by their use more uniform and fast to rubbing. For similar purposes they may be used with pigments and paints as well as being useful as a. protective film and dispersing agent for ceramic colors and as a bodying agent and solvent in printing oils.

Products which are sufficiently soluble in lipoids, may be employed in preparations for oiling, sizing or finishing and as softening agents for textiles and also in the production of salves, cosmetic and pharmaceutical preparations, greasing agents, stuffing agents, fat thickening agents, cutting, or boring oils, polishing masses, agents for protecting the surface of metals from corrosion as well as additions to lacquers, varnishes and paints.

The polymers may be used as preservatives and plasticizers for synthetic and natural rubber, caoutchouc and the like which may or may not be vulcanized and may also be employed as an anti-squeak fluid with or without graphite.

The liquid to solid polymers can be used as such or in mixture with materials having known cleaning, wetting and dispersing powers which otherwise serve to bring the polymerization products into a form specifically desired for use. As such addition agents may be mentioned by way of example, soaps, Turkey red oils, mineral oils and fatty alcohol sulphonates, alkylated naphthalene-sulphonic acids, glue, gelatine, casein, sulphite cellulose Waste liquor, water-soluble gums, mucilages, alcohols, ketones, hydrocarbons, halogenated hydrocarbons or mixtures of these substances. The liquid or solid polymers may be used in dressing and sizing of natural yarns such as cotton, wool, silk, etc., and the synthetic yarns such as cellulose acetate, polyamide, casein, regenerated cellulose, etc. These polymers may likewise be found to be applicable for use in shrink-proofing of wool to improve the appearance and feel of the product.

The polymers and more particularly the high molecular weight polymers are suitable as plasticizers, elasticizers and softening agents for the addition to regenerated cellulose, the cellulose esters, such as cellulose formate, cellulose acetate, cellulose nitrate, cellulose acetonitrate, cellulose acetopropionate, cellulose butyroacetate and similar mixed esters of cellulose including the water sensitive cellulose derivatives, prior to or subsequent to film and filament formation. The polymers are likewise applicable in substantially the same capacity for addition to the relatively water-insoluble cellulose ethers, such as ethyl cellulose and methyl cellulose. They likewise may be added to the synthetic resins, such, for example, as the esters of acrylic and methacrylic acid and their derivatives and more especially the monomers and polymers of methyl methacrylate, methacrylonitrile, acrylonitrile, methyl acrylate and the other monomeric and polymeric esters and derivatives of acrylic and a substituted acrylic acids; and to the monomeric and polymeric vinyl resins such as vinyl alcohol, vinyl acetate, vinyl chloride, vinyl chloracetate, styrene, the polymerized olefines, polymeric ethylene oxides, and polymeric compounds generally.

The liquid to solid water-soluble polymers may likewise be used as water-soluble lubricants for rubber molds, on textile fibers, and in metal forming operations, and as a lubricant and coolant in cutting, drilling, and machining operations.

The polymers generally may be used advantageously as plasticizers or softeners for use in materials such as casein, glue, gelatine, cork, printing inks, Water-soluble art crayons, shoe dressings (white or colored), water paints, paper coatings, kalsomine, plaster and sizing materials, and hair dressings for permanent waves.

The polymers may likewise be found to be useful as addition agents for preparing oil well drilling muds, for modifying natural and synthetic waxes; dispersing agents and ingredients for fungicides, insecticides, sprays, etc.; as a fumigant, as a scrubbing liquid in air purification; and as a heat transfer medium; as an assistant in textile spinning baths, for twist setting of yarns, for crease and crinkle proofing fabrics; for making oil resistant fabrics, and for delustering synthetic yarns; for crease proofing of paper, humectant for addition to tobacco; as an extractant for tobacco, coffee, oil, to extract albumin from dried milk and as a vitamin extractant; for treating fruits, foods, etc., by vacuum pressure injection to hasten ripening process; as a frost inhibitor in drying oils; as a plasticizer for polyvinyl acetals; ice formation inhibitor in gas mains, refrigeration systems, and oil lines; embalming fluid; as an aid in grinding cement clinker, and as a binder for abrasives. The high molecular weight polymers in the form of a film may be used as a substitute for transparent and opaque films for wrapping comestibles and for other extended film uses. Films of the polymers may be coated, if desired, with suitable compositions to render them water insoluble.

I claim:

1. A process for the homopolymerization of 1,3-dloxolane which comprises polymerizing under substantially anhydrous conditions 1,3-dioxolane with itself in a reaction in which 1,3-dioxolane is the sole added reactant in the presence of an acid polymerization catalyst, and prior to recovering the polymeric 1,3-dioxolane, neutralizing the catalyst, the process being conducted in the absence of ethylene glycol.

2. A process for the homopolymerization. of 1,3-dioxolane which comprises subjecting 1,3-dioxolane to polymerization with itself in a reaction in which 1,3-dioxolane is the sole added reactant under anyhydrous conditions and in the presence of an acid polymerization catalyst, and after the polymer. has been obtained, neutralizing the catalyst, the process being conducted in the absence of ethylene glycol.

3. In a process for the homopolymerization of 1,3-dioxolane, the steps which comprise heating 1,3-dioxolane in contact with an acid polymerization catalyst; when preliminary polymerization has proceeded to the desired extent, separating the unpolymerized, 1,3-dioxolane from the the polymers formed; and subsequently increasing the molecular weight of the polymers by again contacting the polymer with a polmerization catalyst.

4. The process for the homopolymerization of 1,3-dioxolane which comprises heating under refiux and to a temperature of approximately C. 1,3-dioxolane in contact with sulfuric acid as the catalyst; when polymerization has proceeded to the desired extent, cooling the reaction mixture and removing under reduced pressure the unconverted 1,3-dloxolane by distillation from the polymers formed, and subsequently increasing the molecular weight of the polymer at a temperature of approximately 100 C.

SEARCH PM in which a: is at least 10;

7. A saturated homopolymer of 1,3-diox0lane fiber exhibiting molecular orientation parallel to its axis.

8. Crystalline homopolymers of 1,3-dioxolane.

9. Crystalline homopolymers of 1,3-dioxolane exhibiting molecular orientation.

WILLIAM F. GRESHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,095,320 Dreyfus Oct. 12, 1937 2,098,108 Reppe Nov. 2, 1937 2,187,081 Hodgins Jan. 16, 1940 2,340,907 Sussman Feb. 8, 1944 2,350,350 Gresham June 6, 1944 2,360,477 Dahle Oct. 17, 1944 2,394,910 Gresham Feb. 12, 1946 Certificate of Correction Patent No. 2,457,224. December 28, 1948.

WILLIAM F. GRESHAM It is hereby certified that errors appear in the printed specification of the above numbered patent requiriaag; correction as follows:

Column 2, line 25, for the Words or inert read on inert; column 6, lines 25 and 26, Example 5, for

(ocmcrnoom) CHaOCHgCHgO and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 3rd day of May, A. D. 1949.

(O CH CH O CH1),

read

dmoomomo THOMAS F. MURPHY,

Assistant Gonwnissz'oner of Patents. 

